For neutralization studies, two different protocols were followed. (a) A fixed amount of venom was incubated with various concentrations of batimastat for 30 min at 37 8C. Then, mice were injected with aliquots of the mixtures containing either two or three LD50s by either the ip or the iv routes. The volume of injection by both routes was 100 ml. Controls received either venom alone,
PBS–Tween alone or batimastat alone. Deaths occurring during a 48 h interval were recorded.